Field of the Invention
The present invention relates to a liquid discharge head and a liquid discharge apparatus.
Description of the Related Art
Liquid discharge apparatuses that perform recording by discharging liquid onto a recording medium use a liquid discharge head 3 that has a pressure chamber communicating with a discharge orifice, and a recording element that provides energy to discharge liquid within the pressure chamber. The liquid discharged from the discharge orifice, such as ink or the like, has had some sort of component added to a medium. There are cases where the medium component vaporizes and evaporates form the discharge orifice, resulting in increased viscosity of the liquid near the discharge orifice. Increased viscosity near the discharge orifice affects discharge properties, and may deteriorate recording image quality. Accordingly, there is known a technology where the liquid is made to circulate through the pressure chamber where the discharge orifice and the recording element is provided, thereby achieving higher quality recording (PCT Japanese Translation Patent Publication No. 2014-510649). However, complicated channels need to be formed within the liquid discharge head in order to circulate the liquid, so this is a factor increasing the size of the liquid discharge head. On the other hand, there is demand for reduction in size in liquid discharge heads with the same number of recording elements disposed in high density, to perform high-definition recording. Although liquid discharge heads generally have recording elements formed on one surface of a board, there is technology where grooves serving as channels for liquid are provided on the rear surface of the board, and through channels are formed passing through the board and communicating with the grooves, thereby realizing reduction in the size of the liquid discharge head (U.S. Patent Application Publication No. 2005/0157033).
In a case of making a configuration where liquid is circulated for example, there is the need to form complicated channels, so the liquid discharge head tends to become larger in size. On the other hand, the arrangement where grooves serving as channels for liquid are provided on the opposite face of the board as the face where the recording elements are provided, and through channels are formed passing through the board and communicating with the grooves, have the following problem. That is to say, in a case where the board is made smaller, the paths that the liquid passes through (the channels and through channels formed as grooves) become narrower as a matter of course, and viscous resistance increases. Increased viscous resistance increases pressure drop, which tends to deteriorate recording quality, such as replenishing of the liquid to the pressure chamber when discharging becoming slower, the amount of liquid discharged onto the recording medium being insufficient, and so forth. Particularly, in an arrangement where circulation of liquid is performed in the configuration where channels are formed on the other face of the board, the pressure drop tends to be particularly great since liquid is flowing at all times, so there is concern that recording quality may deteriorate.